Techniques of collecting particles contained in a fluid that flows through piping or the like include, for example, those described in PTLs 1 and 2.
PTL 1 describes a method of separating and removing particles contained in a steam current.
In this method, a main steam pipe is bent in a vertical direction from a horizontal direction. Moreover, in this method, after bending, the main steam pipe is branched into the vertical direction and the horizontal direction to create flow paths in the vertical direction and the horizontal direction.
Accordingly, steam and particles in the main steam pipe are changed in flow direction from the horizontal direction to the vertical direction by a bent part, and flow straight in a vertically downward direction under the influence of an inertia force and gravity generated in the vertical direction. Thereafter, most of the particles in the steam continue flowing straight in the vertically downward direction within a branch part. Meanwhile, since the steam is not influenced by the inertia force and gravity as much as the particles, the steam flows to the main steam pipe, which is branched in the horizontal direction, while containing some of the particles at the branch part. Accordingly, the particles in the steam that flows in the horizontal direction after the branching can be reduced.
Additionally, PTL 2 describes a method of separating and collecting fine metal powder that is mixed in air during noble metal polishing work, such as ring processing or dental technical work.
In this method, mainly the fine metal powder is separated and collected by changing the wind speed or wind direction of the air that has collected and suctioned dust. That is, after the air that contains the fine metal powder flows straight into a separation and collection device from an air inflow part thereof, the air is increased in wind speed by passing through a hole of which the diameter is reduced. Thereafter, the air is changed in wind direction to a direction intersecting a straight-ahead direction and is discharged by a dust suction machine. On the other hand, since the fine metal powder with high density cannot follow such rapid changes in wind speed and wind direction and flows straight due to its inertia force without changing its direction to the same direction as the air, the fine metal powder can be collected in a metal powder recovery part arranged at an end in the straight-ahead direction.